The present invention relates to an apparatus for sensing a load, and more particularly, to an apparatus for sensing a load applied by vehicle seat belt webbing.
A conventional vehicle seat belt system restrains an occupant of a vehicle seat. The system includes seat belt webbing anchored to the floor pan of the vehicle, a tongue on the webbing, a seat belt buckle for receiving the tongue, and an apparatus for sensing the tension placed on the seat belt webbing by the occupant. An occupant weight sensor may be associated with the vehicle seat. The weight sensor provides an output signal that indicates a sensed weight of the occupant of the seat. An inflatable vehicle occupant protection device, such as an air bag, is inflated under the control of the weight sensor.
When the vehicle experiences a collision, a source of inflation fluid is actuated by a controller and directs inflation fluid into the inflatable vehicle occupant protection device. The controller receives an output signal from the weight sensor and controls the amount of inflation fluid directed into the inflatable vehicle occupant protection device in response to the output signal from the weight sensor. If the weight sensed by the weight sensor is below a predetermined amount (i.e., a low weight in the seat or no occupant in the seat), then the controller disables the source of inflation fluid to prevent inflation of the inflatable vehicle occupant protection device. The controller thus controls the fluid pressure in the inflatable vehicle occupant protection device and the restraining force provided by the inflatable vehicle occupant protection device based on the sensed weight of the occupant. The controller may also disable the inflatable vehicle occupant protection device.
The seat belt webbing, when buckled about an occupant, may be placed under tension. In this case, the weight sensor may not sense an accurate weight of the occupant. The seat belt tension sensing apparatus can produce an output signal that can be combined with the output signal from the weight sensor by the controller so that a more accurate weight value for the vehicle occupant is produced.
An apparatus that can determine the vertical component of the tension on the seat belt webbing and the angle at which that tension is applied can be utilized by the controller to more accurately determine the weight of the vehicle occupant. Also, such apparatus may determine the type of object in the vehicle seat, such as a child seat.
The present invention relates to an apparatus that includes seat belt webbing, a parallelogram linkage, a sensor lever, and a sensor. The seat belt webbing helps to protect the occupant of the vehicle. The parallelogram linkage includes a first beam and a second beam parallel to the first beam. The first and second beams each bend in response to a load applied by the seat belt webbing. The sensor lever is interposed between the first and second beams. The sensor lever has a connection with the first and second beams that causes the sensor lever to deflect upon bending of the first and second beams. The sensor senses the deflection of the sensor lever and provides an output signal indicative of the amount bending of the first and second beams and, therefore, the amount of load applied by the seat belt webbing.